The present invention relates to a method and to an apparatus for establishing connections between neighboring rod-shaped articles by means of adhesive-coated uniting bands. More particularly, the invention relates to improvements in a method and in an apparatus for joining successive groups or arrays of at least two coaxial rod-shaped articles each by resorting to flexible patches of paper, imitation cork or like wrapping material, especially for assembling components of smokers' products.
It is known to assemble the constituents of filter cigarettes or analogous rod-shaped smokers' products on a rotary drum-shaped conveyor whose periphery receives a succession of discrete adhesive-coated uniting bands and groups of coaxial rod-shaped articles. The groups are attached to the respective uniting bands in such a way that they are in linear contact therewith during transport toward a so-called rolling gap wherein the groups are caused to rotate about their respective axes with the result that the corresponding uniting bands are convoluted therearound and are thereby converted into tubular connectors capable of holding the neighboring articles of a group against any movement relative to each other as well as of establishing fluidtight seals in the regions where the neighboring articles of a group abut against each other.
The rod-shaped articles which can be treated in accordance with the method and in the apparatus of the present invention can constitute or can form part of smokers' products. Typical examples of such articles are tobacco-containing plain cigarettes, cigarillos or cigars and filter rod sections of unit length or multiple unit length. For example, filter cigarettes are normally produced in so-called filter tipping machines wherein pairs of plain cigarettes of unit length are assembled with filter rod sections of double unit length preparatory to draping of adhesive-coated uniting bands around the filter rod sections and around the adjacent end portions of the plain cigarettes so that each of the resulting unitary rod-like bodies constitutes a filter cigarette of double unit length. Successive filter cigarettes of double unit length are thereupon severed midway across the filter rod sections so that each thereof yields two filter cigarettes of unit length. Typical examples of such filter tipping machines are those known as MAX and MAX S, produced by the assignee of the present application. Reference may be had, for example, to commonly owned U.S. Pat. No. 4,280,187 granted July 21, 1981 to Joachim Reuland et al. which illustrates a MAX S machine.
U.S. Pat. No. 3,470,884 granted Oct. 7, 1969 to McArthur discloses a portion of a filter tipping machine wherein a continuous web is subdivided into a series of spaced-apart uniting bands on a first drum-shaped conveyor, wherein successive uniting bands of such series are connected with groups of rod-shaped articles on a second drum-shaped conveyor, and wherein such groups (and the adhesive coated uniting bands which are in linear contact therewith) are transferred onto a drum-shaped rolling conveyor which transports the groups through a rolling gap defined in part by the concave surface of a stationary rolling member so that the groups are compelled to rotate about their respective axes and cause the associated uniting bands to be convoluted therearound. FIG. 2 of this patent shows that the uniting bands are convoluted around filter rod sections of double unit length and that the resulting filter cigarettes of double unit length are thereupon converted into filter cigarettes of unit length.
Commonly owned U.S. Pat. No. 3,527,234 granted Sept. 8, 1970 to Hinzmann discloses a similar filter tipping machine wherein the rolling gap is designed in such a way that each group of rod-shaped articles enters and leaves at least one flute at the periphery of the drum-shaped rolling conveyor. The patent to Hinzmann further discloses and illustrates the possibility of severing the web directly on the rolling conveyor and of applying discrete groups to successive uniting bands on the rolling conveyor upstream of the rolling gap.
During transport of groups of rod-shaped articles toward the rolling gap, the groups adhere to the respective uniting bands on the rolling conveyor exclusively as a result of linear or substantially linear contact between the articles of a group and the adhesive-coated side of the respective uniting band. In many instances, the path along which the groups of articles and the respective uniting bands advance on the rolling conveyor toward the rolling gap is relatively long; this should enable the adhesive to set (at least in part) and to thus prevent relative movement between the articles of a group and the respective uniting band. Such mode of transporting groups of coaxial rod-shaped articles and uniting bands toward the rolling gap is satisfactory as long as the speed of the rolling conveyor does not exceed a certain value at which the centrifugal force is sufficiently pronounced to effect a separation of rod-shaped articles from the uniting bands and/or separation of uniting bands (which are normally attracted by suction) from the periphery of the rolling conveyor. At the present time, filter tipping machines turn out up to and even in excess of one hundred cigarettes per second, i.e., approximately 6000 cigarettes per minute. The output of such machines is in the process of being greatly increased (the contemplated output is in the range of 10,000 cigarettes per minute). At such speeds, the conveyors which transport the constituents of filter cigarettes are incapable of preventing the constituents from flying away under the action of centrifugal force and/or of moving relative to each other with attendant reduction of quality of the ultimate products. Therefore, the speed of conveyors in existing filter tipping and analogous machines cannot be increased at will for the purpose of increasing the output to the aforementioned limit because this would entail the production of excessive numbers of rejects and would increase the frequency and duration of down times with attendant additional pronounced losses in output.